Nuprl Lemma : in-hull-leftmost

g:OrientedPlane. ∀xs:{xs:Point List| geo-general-position(g;xs)} .
  (2 < ||xs||
   (∀i,j:ℕ||xs||.
        ((¬(i j ∈ ℤ))
         ij ∈ Hull(xs)
         (∃x:{k:ℕ||xs||| (k i ∈ ℤ)) ∧ (k j ∈ ℤ))} 
             ∀y:{k:ℕ||xs||| (k i ∈ ℤ)) ∧ (k j ∈ ℤ))} ((¬(x y ∈ ℤ))  (↑iy))))))


Proof




Definitions occuring in Statement :  in-hull: ij ∈ Hull(xs) left-test: jk geo-general-position: geo-general-position(g;xs) oriented-plane: OrientedPlane geo-point: Point length: ||as|| list: List int_seg: {i..j-} assert: b less_than: a < b all: x:A. B[x] exists: x:A. B[x] not: ¬A implies:  Q and: P ∧ Q set: {x:A| B[x]}  natural_number: $n int: equal: t ∈ T
Definitions unfolded in proof :  all: x:A. B[x] uall: [x:A]. B[x] member: t ∈ T implies:  Q uimplies: supposing a prop: not: ¬A subtype_rel: A ⊆B int_seg: {i..j-} so_lambda: λ2x.t[x] so_apply: x[s] false: False guard: {T} listp: List+ or: P ∨ Q sq_type: SQType(T) uiff: uiff(P;Q) and: P ∧ Q exists: x:A. B[x] bnot: ¬bb ifthenelse: if then else fi  btrue: tt assert: b bfalse: ff band: p ∧b q iff: ⇐⇒ Q rev_implies:  Q upto: upto(n) from-upto: [n, m) lt_int: i <j top: Top less_than: a < b squash: T less_than': less_than'(a;b) cons: [a b] nat_plus: + nat: decidable: Dec(P) satisfiable_int_formula: satisfiable_int_formula(fmla) lelt: i ≤ j < k ge: i ≥  le: A ≤ B bool: 𝔹 unit: Unit it: nequal: a ≠ b ∈  cand: c∧ B sq_stable: SqStable(P) comparison: comparison(T) hull-cmp: hull-cmp(g;xs;i;j) true: True
Lemmas referenced :  hull-cmp_wf in-hull_wf istype-int set_subtype_base lelt_wf length_wf geo-point_wf int_subtype_base istype-void int_seg_wf istype-less_than list_wf euclidean-plane-structure-subtype euclidean-plane-subtype oriented-plane-subtype subtype_rel_transitivity oriented-plane_wf euclidean-plane_wf euclidean-plane-structure_wf geo-primitives_wf geo-general-position_wf filter_type bnot_wf eq_int_wf bool_cases subtype_base_sq bool_wf bool_subtype_base eqtt_to_assert band_wf btrue_wf bool_cases_sqequal eqff_to_assert assert-bnot neg_assert_of_eq_int bfalse_wf upto_wf subtype_rel_list assert_wf not_wf equal-wf-base istype-assert iff_transitivity iff_weakening_uiff assert_of_bnot assert_of_eq_int assert_of_band list-cases length_of_nil_lemma filter_nil_lemma product_subtype_list length_of_cons_lemma upto_decomp2 add_nat_plus add_nat_wf length_wf_nat decidable__le full-omega-unsat intformnot_wf intformle_wf itermConstant_wf int_formula_prop_not_lemma int_formula_prop_le_lemma int_term_value_constant_lemma int_formula_prop_wf istype-le decidable__lt intformless_wf int_formula_prop_less_lemma nat_plus_properties int_seg_properties add-is-int-iff intformand_wf itermVar_wf itermAdd_wf intformeq_wf int_formula_prop_and_lemma int_term_value_var_lemma int_term_value_add_lemma int_formula_prop_eq_lemma false_wf subtract_wf non_neg_length itermSubtract_wf int_term_value_subtract_lemma filter_cons_lemma map_cons_lemma filter_wf5 map_wf l_member_wf ifthenelse_wf cons_wf comparison-max_wf set-valueall-type int-valueall-type left-test_wf sq_stable__assert l_all_iff le_wf member_filter and_wf equal_wf member_upto2 subtype_rel_set nat_wf int_seg_subtype_nat istype-false l_member-settype
Rules used in proof :  cut introduction extract_by_obid sqequalSubstitution sqequalTransitivity computationStep sqequalReflexivity lambdaFormation_alt hypothesis sqequalHypSubstitution isectElimination thin hypothesisEquality promote_hyp independent_isectElimination universeIsType sqequalRule functionIsType equalityIstype applyEquality intEquality lambdaEquality_alt natural_numberEquality because_Cache setElimination rename sqequalBase equalitySymmetry inhabitedIsType setIsType instantiate dependent_set_memberEquality_alt dependent_functionElimination unionElimination cumulativity equalityTransitivity independent_functionElimination productElimination dependent_pairFormation_alt voidElimination setEquality productEquality isect_memberEquality_alt independent_pairFormation baseApply closedConclusion baseClosed productIsType imageElimination hypothesis_subsumption addEquality approximateComputation applyLambdaEquality pointwiseFunctionality int_eqEquality equalityElimination imageMemberEquality

Latex:
\mforall{}g:OrientedPlane.  \mforall{}xs:\{xs:Point  List|  geo-general-position(g;xs)\}  .
    (2  <  ||xs||
    {}\mRightarrow{}  (\mforall{}i,j:\mBbbN{}||xs||.
                ((\mneg{}(i  =  j))
                {}\mRightarrow{}  ij  \mmember{}  Hull(xs)
                {}\mRightarrow{}  (\mexists{}x:\{k:\mBbbN{}||xs|||  (\mneg{}(k  =  i))  \mwedge{}  (\mneg{}(k  =  j))\} 
                          \mforall{}y:\{k:\mBbbN{}||xs|||  (\mneg{}(k  =  i))  \mwedge{}  (\mneg{}(k  =  j))\}  .  ((\mneg{}(x  =  y))  {}\mRightarrow{}  (\muparrow{}x  L  iy))))))



Date html generated: 2019_10_16-PM-01_40_38
Last ObjectModification: 2018_12_21-PM-11_02_21

Theory : euclidean!plane!geometry


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